Thurman, Romero & Prevost
Printed on 5/19/2015
The Yin and Yang of
Photosynthesis
Day vs. Night
.
Focus on Inquiry
Students will design an experiment to observe the products of photosynthesis in a lab setting. Students
will use a model of photosynthesis to make predictions about the outcomes of manipulating the inputs for
photosynthesis.
Lesson Content Overview
This lesson is meant to be a supplement to the, “Photosynthesis Introduction” Lesson in which student
created a mode showing the inputs and outputs of photosynthesis. Students will use this model to
understand how changing the conditions for photosynthesis affects the photosynthetic products.
Duration
Setting
Grouping
PTI Inquiry Subskills
50 minutes
Laboratory or
Classroom
2 Students
1.1, 1.3, 2.1, 3.1, 3.2, 3.3, 3.7,
4.3,, 5.2, 5.3, 5.9,7.1,7.2
Inquiry
Subskills
Used
Technology
Used
5 min.
1.1, 1.3,
2.1,
Blackboard,
overhead,
etc.
2
Explore
20 min.
2.1, 3.1,
3.2, 3.3,
3.7, 4.3,
Lab
Equipment
Specified in
Materials
3
Explain
5
4.3,, 5.2,
5.3,
,7.1,7.2
Expand
10
Evaluate
10
Lesson
Components
Engage
Estimate
d Time
5.9
Level of
Student
Engagement
3
2
Brief Description
As a class, draw out a visual model of the
photosynthetic process on the blackboard, etc.
A series of probing questions (Appendix A)
can be asked to the class to make sure that all
relevant factors are included.
Students will design an experiment to
measure oxygen production from
photosynthesis. Students will measure how
much oxygen has been produced by the lab
set up (high light vs. low/no light) over the
specified time frame. Data will be collected,
plotted on a graph, and compared among the
class.
Students will work in pairs and answer a
series of questions explaining what occurred
during the experiment. (What gas was
increasing, what was decreasing, etc?)
Students discuss what they think would
happen in situations where other
photosynthetic variables changed like
temperature, carbon dioxide availability, etc.)
1
Level of Student Engagement
1
2
Low
Moderate
Listen to lecture, observe the teacher, individual reading, teacher demonstration, teacher-centered instruction
Raise questions, lecture with discussion, record data, make predictions, technology interaction with assistance
Photosynthesis Day v.
Night
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Thurman, Romero & Prevost
3
High
Printed on 5/19/2015
Hands-on activity or inquiry; critique others, draw conclusions, make connections, problem-solve, student-centered
Next Generation Science Standards – Inquiry
NGSS Practice 2:Developing and Using Models
NGSS Practice 3: Planning and Carrying Out Investigations
NGSS Practice 4: Analyzing and Interpreting Data
NGSS Practice 5: Using Mathematics and Computational Thinking
NGSS Practice 6: Constructing explanations
NGSS Practice 7: Engaging in arguments from evidence
NGSS Practice 8: Obtaining, Evaluating and Communicating Information
Next Generation Science Standards – Life Science
MS-LS1 From Molecules to Organisms: Structures and Processes
MS-LS1-(4, 5, and 6)
MS-LS2-4 Ecosystems: Interactions, Energy, and Dynamics
Florida Science Standards - Inquiry
SC.6.N.1.4 Discuss, compare, and negotiate methods used, results obtained, and explanations among groups of
students conducting the same investigation
SC.6.N.3.4 Identify the role of models in the context of sixth grade science benchmarks.
SC.7.N.1.4 Identify test variables (independent variables) and outcome variables (dependent variables) in an
experiment.
SC.7.N.3.2 Identify the benefits and limitations of the use of scientific models.
Florida Science Standards - Life Science
SC.7.L.17.3 Describe and investigate various limiting factors in the local ecosystem and their impact
on native populations, including food, shelter, water, space, disease, parasitism,
predation, and nesting sites.
SC.8.L.18.1 Describe and investigate the process of photosynthesis, such as the roles of light, carbon
dioxide, water and chlorophyll; production of food; release of oxygen.
Materials and Advance Preparation
Materials List
Per Set Up:
● 2 Erlenmeyer Flasks (1000 ml)
● 2 Drilled Rubber Stopper
● 2 1ml syringes
● 2 1 ml pipets
● Elodea
● Water
● Several Large Sheets of Newspaper, etc.
● Tape
● Sharpie or other permanent marker
Blackline Masters
1. Backline Master 1
Advance Preparation
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Thurman, Romero & Prevost
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1. Make sure all materials are clean and free of any chemicals which may adversely affect the
plants.
2. Pick through the elodea to make sure there are no snail, crayfish, or other animals living in the
plants.
3. Take one Erlenmeyer flask and completely cover the outside using newspaper and tape. Make
sure to cover with at least 3 layers since newspaper is very thin. The other flask should remain
clear.
Lesson Information
Learning Objectives
1. The student will be able to describe the process of photosynthesis and its inputs and outputs.
2. The student will be able to correctly (standard) predict, based on their model and data collected in
this experience, how the photosynthetic rate is likely to respond as its variables change.
Prior Knowledge Needed by the Students
● Basic understanding of photosynthesis, its reactants, products, and importance
● Basic understanding of plant structure.
Background Information
Photosynthesis is the primary origin of the earth’s oxygen gas in the atmosphere that most animals
breathe every day. Plants conduct photosynthesis mainly in their leaves which obtain water via the
roots and carbon dioxide from the air. In the leaves, these inputs – water and carbon dioxide, react
with sunlight to produce glucose, oxygen, and water. The glucose formed is stored in the plant
tissues and forms the basis of most food webs, as plants are many animals. Numerous
environmental parameters influence the rate of photosynthesis in plants. Increased light availability,
carbon dioxide, and water will all increase photosynthetic rates up to a point, but can be detrimental in
excess. Any changes in photosynthetic rate will affect the reactants (inputs) and products (outputs)
with an increase in photosynthesis resulting in reactants being used up faster and products being
produced faster. Any additional factors affecting the availability of reactants should affect
photosynthetic rate.
Lesson Procedure
Engage
Include guiding questions you might ask to help students. If you use a video (include the URL in your lesson plan instructions) or
a book (the author, title and publication date), and include questions that you would ask before, during or after the video/book
reading selection.
1. Students will review their model of photosynthesis (Created in the photosynthesis introduction
lesson) to refresh their minds and access their background knowledge about the process of
photosynthesis. This can be done using the blackboard, overhead, etc. This can be
accompanied by guiding questions as the student contribute components to recreate their model.
This exercise should be a review of the previous lesson on photosynthesis.
Guiding Question Examples:
Where does photosynthesis occur?
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Thurman, Romero & Prevost
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What is needed for photosynthesis to occur?
What are the products of photosynthesis?
Photosynthesis Inputs = Carbon dioxide + Water + Sunlight
Photosynthesis Outputs = Oxygen+ Water + Glucose
Students will then brainstorm “What do you think will happen to photosynthesis if light if reduced?
They will write down their prediction.
Explore
Experiment Setup
1. Divide the elodea equally into to piles and then
place each pile into a separate flask (one clear,
one blacked out with newspaper).
2. Place a pipette through each drilled stopper.
3. Place a syringe at the top of each pipette.
4. Fill each flask with spring or tap water close to the
top.
5. Securely and snuggly fit the rubber stopper with
the pipette and syringe in the top of the flask and take out or add more water if needed to make
sure the water is within a few mm of the bottom of the stopper.
6. Move the setups to an area where they will not be touched or otherwise disturbed. This should
be an area that receives a high amount of light like a window or under a lamp.
7. When the setups will no longer need to be moved, take the sharpie and mark where the water
level on the syringe.
Lesson Activity
1. When directed the students should take their data sheet over to the setups and record how much
the water in the syringe has moved in each setup.
2. Students will use the data table to construction a simple line graph.
3. The line graph should consist of time (hours or days) on the x axis and ml of water moved on the
y axis. Data sheets and a graph set up can be provided (Blackline Master 1)
Explain
1. Students will write one or two sentences explaining the graph.
2. Each student should determine if his or her prediction (from the Engaged section) was on
confirmed or rejected. Why?
3. Students should then discuss with each other the questions listed in the Explain and Expand
sections of the lesson.
.
Some questions you might ask students include,
1. What differences did you notice between the setups?
2. Why was one different than the other?
3. What gas should be causing the difference in the setup volumes if this is a closed system?
4. What should be happening to carbon dioxide concentrations in the flask?
5. Where are the plants getting carbon dioxide from?
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Thurman, Romero & Prevost
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6. From where on the plants is oxygen released?
Expand
Below are several probing questions with scenarios in which the students can further apply this
lesson to new scenarios. Students can modify their model to help them answer these questions.
a. What would happen to photosynthesis rates if a storm came and it was real cloudy for a couple
days compared to a clear day?
b. What would happen to photosynthesis rates if the water in a lake suddenly got very clear?
c. Based upon today’s lesson on photosynthesis, what might be one reason that plants living in the
desert grow so slow?
d. What would happen to photosynthesis rates if all the carbon dioxide was suddenly gone from the
atmosphere? What if it doubled?
e. What would happen to photosynthesis if a hurricane came through and stripped all the leaves off
of the plant?
f. How would different oxygen levels in the atmosphere affect photosynthesis
g. How would a drought affect photosynthesis?
h. How would deforestation affect photosynthesis?
i. What would happen to oxygen levels on the earth if all the plants suddenly stopped
photosynthesizing?
Evaluate
FORMAL EVALUTION
a. See attachment
WRAP UP.
Bring the lesson to a conclusion by revisiting the process of photosynthesis including what it is, what
it does, where it occurs, and what are the reactants and products of the reaction.
Supplementary Resources
Teachers
Photosynthesis: Light reaction, Calvin cycle, Electron Transport [3D Animation].
https://www.youtube.com/watch?v=joZ1EsA5_NY. Good detailed video on photosynthesis. Is
much too long and needs to be edited but it has good information that could be adapted to
any grade.
__✓__ Yes, I cited all materials and resources used in this lesson.
Paul Thurman,
Margaurete Romero & Luanna Prevost
Lesson author signature
Photosynthesis Day v.
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Thurman, Romero & Prevost
Printed on 5/19/2015
Name ___________________________________________
1.
Date _________________
A) Draw your model of photosynthesis below.
B) Show how your model will be different under the conditions of the experiment. You can either redraw
your model here. Or make changes to your original model above using a different color pen/pencil.
2. Include your data from the experiment in the table below.
Photosynthesis and Light Experiment Data Sheet
Plant receiving light
Time
0
Water Level
Plant receiving no light
Time
Water Level
0
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3. Plot the data from your table above on this graph below.
4. Write 1-2 sentences explaining what your graph shows.
5. a. Was your prediction confirmed or rejected.
b. Why do you think this is so?
6. Photosynthesis can be affected by many environmental conditions. In this experiment, we have
investigated how light and dark conditions affect photosynthesis.
a. Can you think of one more situation/condition where you can use model to make predictions
about how photosynthesis will be affected?
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Thurman, Romero & Prevost
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b. Can you think of one situation/condition where you CANNOT use model to make predictions
about how photosynthesis will be affected? (Note: this is called a limitation of a model).
c.
Why do you think models have limitations?
Name ___________________________________________
Date _________________ Student No. ___________
Checking for Understanding: PHOTOSYNTHESIS
___ 1. Which of the following is NOT an input or output of photosynthesis?
A. Carbon dioxide
C. Water
B. Oxygen
D. Temperature
___ 2. If photosynthesis stopped today, the earth would still have enough oxygen for
animals to survive indefinitely.
A. True
B. False
Explain your answer.
3. List two variables could you change if you wanted to increase the rate of photosynthesis.
4. Why did it take so long for oxygen levels to increase on earth?
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